Final answer:
Becky's parents are using omission training by employing punishment through the deduction of money, a positive secondary reinforcer, to decrease her swearing habit.
Step-by-step explanation:
Becky's parents are employing a behavior modification strategy known as omission training, specifically, they are using punishment; the removal of a positive secondary reinforcer. In this context, the allowance Becky receives is not a primary reinforcer like food or water, which satisfy basic biological needs, but rather a secondary reinforcer because it holds value due to its association with primary reinforcers and social currency. Deducting money from Becky's allowance for swearing is intended to decrease the frequency of the unwanted behavior, hence it qualifies as punishment. Moreover, since this approach involves the removal or omission of a reinforcing stimulus (the allowance money), it confirms that omission training is being used.